Some of our customers request that we ice liquid yeast for transit. We offer this service to anyone who lives in a hot climate or feels they would like the service. Will the yeast be in better health when they arrive at your door? Yes.,,So while you can achieve a good ferment without paying for ice the yeast will most likely have increased viability if shipped with ice and that means a faster start (we always recommend ice when shipping liquid yeast). Faster starts reduce lag times and the risk of off flavors. The ice will keep yeast cool for 1-3 days depending on temperatures. This at least extends the time they stay cool while in transit to you. You can order as many packs as you like. If you are purchasing multiple vials we do recommend ordering multiple ice packs.